Electric clock movement



Feb. 7, 1939. F. R. BUTHERUS 2,146,499

ELECTRIC CLOCK MOVEMENT Filed Aug. 14, 1936 2 Sheets-Sheet l Jnuerur Jredeu'ch 7305 @ufhemas Feb. 7, 1939. F R B UQ 2,146,499

ELECTRIC CLOCK MOVEMENT Filed Aug. 14, 1936 2 Sheets-Sheet 2 Jhdenlbr mdembfi/ Roy Buiherus lflz'u/w Patented Feb. 7,1939 2,146,499

UNITED STATES PATENT OFFICE ELECTRIC CLOCK MOVEMENT Frederick Roy Butherus, Enfleld, England, assignirlrl to Sangamo Electric Company, Springfield,

Application August 14, 1936, Serial No. 96,011 In Great Britain January 16, 1936 1 Claim. (CI. 58-28) The present invention relates to improvements device indicated generally by 8. The escapement in electric clock movements and is more particudevice comprises a balance wheel 9 which operlarly concerned with a clock movement in which ates a pallet IOcontrolling the escape wheel II. the time shaft is normally driven by a synchro- The escape wheel is also connected to the first nous electric motor while when the motor fails'the element of the ball clutch 5 through a train of t me shaft is driven by auxiliary spring driving gearing l2. The balance wheel 9 is provided with moans under the control of an escapement dea pin 13 fixed to its periphery. The means for vice. locking the balance wheel in an extreme posi- An object of the invention is to provide means tion comprises a soft iron member 14 arranged whereby when the synchronous motor fails the adjacent to the synchronous motor. The member in spring driving means and the escapement device is pivoted about the fixed point I5 and is are brought into operation with the minimum formed integral with a boss IS- The boss I6 also delay, carries an arm 11 by means of two brackets 18,

A feature of the invention relates to the use of one end of the arm being bent as shown at l9.

15 a mechanical locking device controlled by the A blade spring is fixed to the arm I! at a point 15 field of the motor and arranged to stop the remote from both ends, and one end of the spring escapement device in a position of maximum po 20 is bent over at 22 while at the other end the ten'tial energy so that when the motor fails the Spring is bent away from the arm and engages escapement is rapidly released and takes over the with a fixed post 2|.

:0 control of the time'shaft. The operation of the clock is as follows. As "0 A further feature of the invention relates to sume that the spring is driving the clock, the synihe use of a differential device between the motor ohronous motor having ceased to operate. when and the time shaft so arranged that when the the synchronous motor again starts and drives motor drives the time shaft, the escapement and the time shaft 4 through the gearing 2 and ball one of the sun wheels are locked while when the clutch 3, the magnetic member I4 is acted upon 25 motor fails the sun wheel is released, the other by the leakage fiux from the motor and takes up sun wheel is locked and the time shaft is driven the dotted position against the tension of the by the spring under the control of the escapement spring 20 acting on the post 21 as shown in Fig. 2. device, the spring being wound by the synchro- The movement of the member H from the fullnous motor. line to the dotted position causes a similar move- 30 The invention will be better understood from ment on the part of the arm I 1 from the full-line the following description of two embodiments to the dotted position. The end 22 of the blade taken in conjunction with, the accompanying Spring 20 is now in the path of the pin 13 fixed drawings in which: to the balance wheel. The direction of oscilla- Fig. 1 shows a perspective view of the clock tion of the balance wheel from the position shown 35 movement and in Fig. 2 is indicated by the arrow and it will be Fig. 2 shows an elevation of the locking means, app eciated that the p '3 t wa ds the 8nd of and an oscillation will strike the underside of the Fig. 3 shows a form of ball clutch which is spring blade. Now the spring since it is fixed to 40 particularly suitable for use in the movement. the arm I 1 at a point remote from its ends allows 40 Fig. 4 shows an alternative drive between the the pin l3 to passwhen moving'in an upward synchronous electric motor and the time shaft. direction but does not let it pass when moving in Referring more particularly to Fig. l, a selfa downward direction, so that the balance wheel starting synchronous electric motor I drives is stopped in the position shown in Fig. 2 which is 4:, through gearing 2, one element of a ball clutch 3, the position 01' maximum potential energy. The the other element of which is fixed to the time spring-drive to the clock is therefore interrupted. shaft 4. A second ball clutch 5 is also mounted When .the synchronous motor stops for instance on the time shaft 4, and the first element is driven due to an interruption in the current supply the by the reserve power which takes the form of a leakage field collapses and the member H returns spring housed in a barrel 6. The spring is wound to the full-line position under the action of the by the synchronous motor I through the gear 1, a spring 20. The arm II also returns to the fullslipping connection existing between the spring line position and the end 22 of the spring 20 is and the barrel to prevent overwinding. When removed from under the pin 13 whereupon the the spring is driving the time shaft, the rate at balance wheel is released and the spring-drive which it unwinds is controlled by an escapement operates the time shaft. ll

Fig. 3 shows a suitable form of ball clutch for use at 3 and 5. The clutch is formed with an Outer toothed ring 25 which forms one element of the clutch. Within this ring is a circular disc 25 fixed to the time shaft 4 and provided with a number of notches such as 21. A cover plate 28 having a larger diameter than the disc 26 is bolted to the disc. In each of the notches 21 is located a ball 29 against which presses a spring 30. If the ring 25 is rotated in an anti-clockwise direction the ball will jam against the ring and a solid drive to the time shaft will be effected. If, however, the time shaft is rotated in an anticlockwise direction the ball will be pressed against the spring, the disc will slip inside the ring. and the latter will not be rotated.

Referring now to Fig. 1 if the synchronous motor is driving the clock, the ring of the clutch 3 is rotated in an anti-clockwise direction and carries the second element, the time shaft and the second element of the clutch 5- with it. The movement of the second element of the clutch 5 however will not be transmitted to the first element and hence the escapement device will not be subjected to any undue strain. The reverse occurs of course when the time shaft 4 is driven by the spring under the control of the escapement device and the motor is stationary.

Manually-operable means are also provided 'whereby the spring-driving means can be permanently prevented from driving the time shaft. Thus in Fig. 2 the member 23 is manually rotatable and carries a pin 24 which when the member 23 is rotated in an anti-clockwise direction takes up the position shown in dotted lines thereby causing the end 22 of the spring 20 to be moved into the path of the pin [3. The member 23 can berotated from outside the casing of the clock by a rotatable knob or othersuitable means.

Fig. 4 shows an alternative drive between the gear trains 2 and i2 and the time shaft 4. The

escapement device is connected, through the gear train i2 and the gear wheels 3|, to one of the sun wheels 32 of a differential device indicated generally by 33. Formed integral with the sun wheel 32 is a gear wheel 34 which meshes with a gear wheel 35 formed integrally with the spring barrel 36. One end of the spring 31 is in frictional engagement with the barrel 36 while the other end is attached to a shaft 38 which carries a gear wheel 39 meshing with the'second sun wheel 40 of the differential. Both sun wheels are mounted loosely on the time shaft 4 while the planet carrier 4| is rigidly mounted thereon.

The synchronous electric motor is connected to the gear train 2 and controls through gearing 42 the movement of the sun wheel 40.

The operation of this arrangement is as follows: When the synchronous motor is inoperation the escapement device is locked as before and hence the sun wheel 32 is locked and the motor drives the time shaft 4 through the gearing 2, 42, the sun wheel 40 and the planet carrier 4|. Further the spring is wound up through the gear 39. When the synchronous motor fails the sun wheel 32 and the escapement device are released and the sun wheel 40 is locked. The time shaft 4 is then driven by the spring 31, through gear wheels 35, 34 and sun wheel 32 to the planet carrier 4! under the control of the escapement. It is to be noted that in this construction no strain is applied to the planet wheel of the differential, since the winding of the spring is effected independently of the differential.

It will be appreciated that the invention is not limited to the constructions shown but various modifications will be obvious to those skilled in the art all of which fall within the scope of the invention as defined by the following claim.

I claim:-

In a clock disposed to be driven by an electric motor and on deenergization thereof by a spring motor, in combination, balance means including a balance wheel for controlling the functioning of said spring motor, a pin projecting radially from said balance wheel, an arm pivoted about an axis substantially parallel to the axis of rotation of said balance wheel and in substantially the same plane as said balance wheel, an armature extending from said arm and disposed to move the same under the influence of the magnetic field of said motor, and a blade spring member secured to one end of said arm and extending therealong and having its outer end curved and positioned in the path of said pin at a position substantially spaced from its midposition on energization of said motor, said curved outer end portion of said blade spring i being positioned along the side of said arm away from said balance wheel so as to permit said pin to pass the same when it is moving toward said position and away from said mid-position and to prevent movement thereof in the opposite direction, whereby said balance wheel is always stopped in a position of relatively high potential energy on energization of said motor.

FREDERICK ROY BUTHERUS. 

